So I've been tracking a gear oil leak for weeks, studying the forum and google. Common issues are axle seals, usually left side, or a clogged vent.
My leak is on the right side, both axle seals are clean and dry. The external covers also appear sealed. I went ahead and did the vent conversion but didn't see anything wrong with it when I got it off. The leak seemed to diminish but was still there. Another post suggested the o ring between the automatic trans and diff. This made sense due to the location of the oil leak so I cleaned it up good and sealed the bottom externally with permatex for gear oil. With the diff vent conversion there should be zero pressure to push oil out. Didn't see any more oil and thought that was it until yesterday. Figured I needed to seal up the sides to the level of the fill plug but "discovered " a vent hose between the trans and diff venting over the monoleaf. I followed it up to over the trans where there is a plastic thing T'd in that to me resembles a small pcv valve. It looks like it should be connected to either a hose or a grommet like the pcv usually is. I am attaching some photos, or will post following this.
Any idea what this is/does?
The trans fluid is clean and pink, engine doesn't use oil . This is a gear oil leak. I don't see why the diff would have a second vent.
Thanks

 

If you expand the top picture the part in question has the white hose barb looking thing on the end

 

Disregard, located it on page 7-238. Its a transmission vent tube check valve, its not connected to anything because they're using it as a siphon break.
The search continues for the leak��

 

Good info, though. And good luck finding the leak.

 

Hope you can find the source of the link. Seems like you've ruled out a lot of the most common areas.